1. Field of the Invention
The present invention relates to a back electromotive force detection circuit capable of accurately controlling driving of a motor by compensating for a delay in back electromotive force by performing delay compensation such that driving control signals have the same delay, while duties thereof are different, and a motor driving control apparatus using the same.
2. Description of the Related Art
In line with the development of motor technologies, motors having various sizes have been used in diverse technical fields.
In general, a motor is driven by rotating a rotor by using a permanent magnet and a coil having polarities thereof changed according to a current applied thereto. Initially, a brush type motor having a coil in a rotor was provided, which, however, had a problem in that a brush thereof was abraded or sparks could be generated.
Thus, recently, various types of brushless motor have been used globally. A brushless motor, eliminating mechanical contact units such as a brush, a rectifier, or the like, is a DC motor driven by using an electronic commutating mechanism instead. The brushless motor may include a stator configured as a permanent magnet and a rotor having coils corresponding to a plurality of phases and rotating by magnetic force generated by phase voltages of the respective coils.
In order to effectively drive a brushless motor, commutation of each phase (coil) of a rotor should be made at an appropriate timing, and for appropriate commutation, a position of a rotor is required to be recognized (i.e., known or detected).
In order to determine a position of a rotor, in the related art, an element such as a hall sensor, a resolver, or the like, is used, but, in this case, a driving circuit may be relatively complicated.
In order to complement this, a technique of driving a brushless motor by recognizing a position of a phase by using back electromotive force (BEMF), replacing a sensor, has been widely used.
However, in the case of using back electromotive force, delays are different according to duties of driving control signals controlling driving of a motor, having a limitation in that it is impossible to accurately detect back electromotive force.
Related art documents below relate to a brushless motor, which, however, do not disclose a technique for overcoming the limitation of back electromotive force in that delays may be different according to duties of driving control signals.